A. Technical Field
The present invention relates to a micromechanical Coriolis rate of rotation sensor (MEMS rate of rotation sensor) for detecting a rate of rotation, comprising a substrate, a measurement axis (X-axis), a detection axis (Y-axis), and a drive axis (Z-axis), each disposed orthogonally to each other. The rate of rotation sensor further comprises a first and a second driving mass disposed in an X-Y plane parallel to the substrate, wherein each driving mass is rotatably connected to the substrate by means of a central suspension. The two central suspensions are disposed along the Y-axis. Drive means for generating a rotational oscillation of the driving masses about the drive axis are further provided at each central suspension.
B. Background of the Invention
A generic rate of rotation sensor using MEMS technology and comprising two driving masses is known from U.S. Pat. No. 5,635,640. Both driving masses are attached to a substrate and disposed displaceably relative to said substrate. The two driving masses are coupled to each other by means of a spring, by means of which the rotary motions of the two driving masses about their corresponding centers of rotation is accomplished. The two driving masses are driven to move by the corresponding drive means, identically and generally in antiphase due to the central spring. If the substrate is rotated about a measurement axis, then a Coriolis force acting on the rotationally oscillating driving masses causes the two driving masses to rotate or tip about a detection axis in an equal and opposite manner. An electrical signal is generated by electrodes disposed between the driving masses and the substrate due to said tilting motion and the resulting change in distance between the driving mass and the substrate, allowing a conclusion to be drawn about the rotary motion of the substrate.
Generic Coriolis rate of rotation sensors are used, for example, in vehicles or other devices in which the sensors can be subject to impacts. A disadvantage of the rate of rotation sensors according to the state of the art is that said sensors are relatively sensitive to such external force influences. Imprecise measurements are thereby obtained, or the sensor can even be damaged.